Clamping device



March 19, 1940. R. F. KNIGHT I 2,193,820

CLAMPING nEvIc'E Filed Feb. 21, 1938 y figg ATTORNEYS.

Patented Mar. 19, 1940 PATENT vorties 2,193,820 y CLAMPING DEVICE Ronald F. Knight, Ramsey, N. J., assigner, by

mesne assignments, to The R. W. Cramer Company, Incorporated, Essex, Conn., a corporation of Connecticut Application February 21, 1938, Serial No. 191,662

4 Claims.

This invention is a novel clamping device adapted for certain uses such as the mounting or clamping of an instrument upon a panel or board, a typical case being the instrument board of an automobile, having perforations to receive the various instruments, such as clocks or other timers, meters, gages, switches, rheostats and the like.

As herein designed the clamping device of this invention is adapted to cooperate to clamp within the round perforation of the panel an instrument havingA a cylindrical housing or barrel which ts the perforation, with a front iiange or lugs contacting the panel at one side, the clamping device being applied at the other or rear side.

An object ci the present invention is to afford a clamping device for the purposes mentioned, or analogous purposes, which will be simple in construction, light of weight and inexpensive of manufacture. Another object is to afford such a device which is readily and conveniently' applied, and indeed may be readily detached at wiil and used again. A further object is to afford a clamping device that will be effective in practical use, affording a snug and tight clamping action of a wedging nature, eliminating looseness and rattle.

By this invention these, objects are attained and other advantages secured. It avoids the need of boring additional holes in the instrument board or otherwise disfiguring the panel surface. The invention permits the instrument to be designed with the very minimum of width of the front ange or lugs, and this in turn permits closer grouping when several instruments are to be mounted on the same panel. The instrument itself may be designed to afford greater lightness and less expense of structure. The device is applicable to panel boards of varying thicknesses.

To the attainment of such objects and advantages the present invention consists in the novel clamping device and the novel features of operation, arrangement and structure herein illustrated or described.

In the accompanying drawing Fig. l is a side elevation of a clock or other instrument mounted upon a panel board by the device of this invention, said gure being partly broken away to show details of arrangement.

Fig. 2 is a rear elevation View, that is, looking toward the left side of Fig. l. Fig. 2a shows a modification.

Fig shows a serrated metal strip of indeiinite length from which may readily be formed clamp- (Cl. 248-27) u' ing devices of various sizes operating according to this invention.

Fig. 4 shows a modied construction in the form of a short extent of development of two cooperating straps. V5

The vgeneral plan o-f the invention is to provide a device comprising two simple cooperating parts which may be attached in sequence to the barrel or housing of the instrument, behind the panel, the clamp part which is furthest from the panel being first tightened on the housing, and then the part which is adjacent t0 the panel being adjusted by rotation to create a wedging pressure, after which it is tightened upon the instrument to hold its position; and the two clamping parts may if desired be substantially identical, each with wedging surfaces as will be described. In some cases the tightening of the ring which is next to the panel may be unnecessary where there is no tendency to loosen. 20

The panel or instrument board lli is shown in vertical position and may be considered as xed. The instrument ll is shown as having a cylindrical housing or barrel, extending loosely through the circular aperture inthe panel and having a c25 slight iiange l2 in front of the panel, which of course need not be continuous and may consist of three or more lugs. This being the desired relation between panel and instrument, the clamping device for securing the instrument in 1;;'30 place will next be described.

There may be first applied to the barrel H a loose Washer I3 contacting against the rear face of the panel, although this washer may equally well be omitted when desired. The clamping de- 35 vice is shown as comprising front and rear clamp members, rings or straps Hi and 2li constituting a cooperating pair. Each of these rings or straps is shown in its preferred form as consisting of a metallic band extending circumierentially aroundia() the instrument barrel, with an inside diameter fitting the barrel, 'first loosely, but tightly when in iinal position.

Referring more in detail to the front clamping element or ring lli this is shown as a curved strip45 of metal having clamping extensions or ears i5 at its ends. 'I'hese ears are in opposed relation and are punched to receive a tightening bolt or screw i6 arranged to extend through the two ears and engaged by a nut il, so that by turning the-.'50 screw the ring l can be contracted into tight clamping pressure upon the instrument barrel.

By Way of cooperating with the rear ring 2li, the front ring, at its rear edge is formed with a series of rearward projections I8, shown in :thejg form of long teeth or serrations, each preferably having a gradually inclined surface I9 affording a wedging or camming action.

Similarly the rear clamp element or ring 20 has clamping ears 2|, tightening screw 22 engaging a nut 23; and the rear ring has front- Ward projections 24, facing the projections I3 of the front ring, and preferably presenting inclined or wedging surfaces 25. It will be understood that it is preferred that the inclined or cam surfaces I9 or 25 are formed upon both clamp members, but should be upon at least one of them, with cooperating projections upon the other. By having the two alike in this respect the two clamping members may be wholly identical, thus simplifying manufacture and application of the invention, a pair of such clamping rings being furnished with each instrument to be mounted upon the panel board.

The mode of mounting the instrument by the clamping device hereof has been indicated. After the instrument has had its barrel inserted through the front of the panel aperture, its front ange being held snugly to the panel, the two clamping rings are applied over the rear end of the barrel, in reverse positions, their serrations or projections facing each other. Initially the two rings are relatively turned so that serrations are closely locked, minimizing the combined width of the two rings. Holding the two rings close to the rear lace of the panel the rear is rst tightened against rearward sliding by means of the screw 22, affording a tight gripping upon the barrel periphery. The front clamp ring is then manually rotated in a direction to give the wedging action described, substantial pressure being applied so that the rear ring and the instrument are thrust relatively rearward, the instrument being thus tightly clamped in position. In eifect the panel is clamped between the instrument front iiange and the front clamping ring. When wedged tightly in position the front ring may then be permanently tightened by means of its screw i6, although in a stationary apparatus, as radio, where there is no vibration the ring may stay wedged without tightening. It is only necessary to slacken the screws for easy removal of 'the device.

The clamping device hereof is cheaply manufactured. A strip 26 cf sheet metal is iirst formed with serrations El as shown in Fig. 3. Clamping rings of a certain diameter being Gesired the strip is cut into the necessary lengths and the holes for receiving the screw are made. The ears at each end are then formed. Application of the screw and nut renders the ring ready for use in cooperation with a duplicate ring, in the manner described. For a given instrument the wedging serrations 2l are preferably of such length that the instrumentJ circumference is an exact multiple thereof; wherefore strips of circumferential length :nay be out and afford perfect cooperation in wedging action. On that plan the sum of the lengths of the two bent ears' will equal the gap between them in Fig. 2St shown.

Various modiiications are available within the principles of the invention. The wedging slants of low pitch cooperate for causing a longitudinal wedging thrust adequate to take up slack and secure the instrument against rattle. By having a suitable pitch of slants liliL on one ring lia, Fig. 4, the other ring 299- may have mere ingers or studs Zfla to cooperate as followers upon cams. The iront ring wedges itself relatively frontward when turned and presses directly upon the panel rear face. The rotatable ring may have several external bosses or knobs to facilitate manual turning, the projecting ears i5 serving such purpose. In cases where the front ring, nearest to the panel, does not need contracting to tighten it, this ring may be a solid ring or section of tube, with the projections or wedging inclines formed thereon to cooperate with the other or stationary ring.

I claim:

1. For securing in a receiving aperture oi a panel board an instrument or article with a generally cylindrical barrel having a iront enlargement or iiange to abut the panel face; a clamping device comprising the combination of front and rear peripheral straps of initial inside diameter to fit loosely around the exterior ol the barrel, each strap having a contracting means to tighten it iirmly around the barrel, and the two straps having cooperating projections, at the front edge of the rear strap and at the rear edge of the front strap, including inclined projections adapted to afford a longitudinally wedging action; whereby, when the straps surround the barrel adjacent to the panel rear side, the rear strap may be tightened to grip the barrel, and the front strap then partly rotated to wedge relatively rearwardly the rear strap and barrel thus to clamp the panel between the barrel iront enlargement and the front strap, and the iront strap then tightened upon the barrel in its rotated position.

2. For securing in a receiving aperture of a panel board an instrument or article with a generally cylindrical barrel having a iront enlargement or ange to abut the panel face; a clamping device comprising the combination of iront and rear peripheral straps of initial inside diameter to t loosely around the exterior ol the barrel behind the panel, the rear strap having a contracting means to tighten it iirmly around the barrel, and the two straps being alike and complementary in each having cooperating lowinclined projections, at the iront edge of the rear strap and at the rear edge of the front strap, respectively, adapted to afford a mutual longitudinally wedging action; whereby the rear strap may be tightened to grip frictionally the barrel, and the front strap then partly rotated to wedge relatively rearwardly the rear strap and barrel thus to clamp the panel between the barrel front enlargement and the front strap.

3. For securing in a receiving aperture of a panel board an instrument or article with a barrel having a front enlargement to abut the panel face; a clamping device comprising the combination of separate front and rear peripheral, sleevelike rings of sutcient inside diameter to permit them to be applied loosely around the exterior of the barrel behind the panel, the rear ring having means to tighten it iirrnly around the barrel, and the two rings formed with cooperating means adapted to afford a longitudinally wedging action when the front ring is relatively rotated; whereby, when the rings surround the barrel the rear ring may be tightened to grip the barrel, and the front ring then rotated to cause a Wedging action thrusting relatively rearwardly the rear ring and barrel thus to clamp the panel between the barrel front enlargement and the front ring.

4. As an article of manufacture to constitute one of two similar complementary members in a. clamping device 0I' the character described, a clamping strap adapted to assume Jshe form of a cylindrical sleeve-like split ring and having a series of wedging serrations alom,r its edge projecting saliently from the ring and thereby adapted for mutual cooperation of such projecting serrations with the corresponding projecting- RONALD F. KNIGHT. 

